The subject invention relates to the treatment of peripheral neuropathies and, more specifically, to the treatment of demyelinating peripheral neuropathies.
By way of background, demyelinating neuropathies or diseases can occur in both the central nervous system and peripheral nervous system. Multiple sclerosis (MS) is a degenerative and inflammatory neurological disease which affects the central nervous system and, more specifically, the myelin sheath. MS causes demyelination of nerve fibers which results in a short-circuiting of nerve impulses and thus a slowing or blocking of transmission along the nerve fibers with associated disabling symptoms including spasticity, loss of motor strength, and painful dysaesthesias (neurogenic pain). In contrast, with peripheral demyelinating neuropathy, spasticity does not occur; however, weakness and neurogenic pain are problematic. Peripheral neuropathies are associated with a number of diseases, syndromes, or conditions including but not limited to acquired diseases or conditions including Guillain-Barre Syndrome (GBS), chronic demyelinating polyradiculoneuropathy (CIDP), diabetic mellitus (prevalence of diabetic neuropathy alone is over one million in the United States), or the hereditary sensory-motor neuropathies (Charcopt-Marie-Tooth disease, Friedrich""s ataxia, porphyria, lipoprotein neuropathies, and familial amyloid neuropathies).
U.S. Pat. No. 5,540,938 to Masterson et al., issued Jul. 30, 1996, and assigned to Elan Corporation discloses a method for the treatment of neurological diseases characterized by central nervous system demyelination such as MS and Alzheimer""s disease, by the administration of mono- or di-aminopyridine to a patient having the central nervous system demyelinating disease. The Masterson et al. patent only teaches the amelioration of symptoms associated with the central nervous system demyelating diseases and does not describe the use of aminopyridines for the treatment of peripheral nervous system demyelating diseases or their symptoms.
U.S. Pat. No. 5,545,648 to Hansebout et al., issued Aug. 13, 1996, and assigned to the Canadian Spinal Research Organization, discloses the use of 4-aminopyridine for the reduction of chronic pain and spasticity in spinal cord injured patients. However, the Hansebout et al. patent only discloses the use of 4-aminopyridine for the treatment of central nervous system diseases and injuries such as spinal cord injury. (See also, Segal et al. (1998) xe2x80x9c4-Aminopyridine Alters Gait Characteristics and Enhances Locomotion in Spinal Cord Injured Humans,xe2x80x9d The Journal of Spinal Cord Medicine, Vol. 21, pp. 200-204.
It is interesting to note that, in general, central nervous system demyelinating diseases such as MS do not cross over to affect the peripheral nervous system as the peripheral myelin is different in both its structure and response to antibodies than is, the central nervous system myelin even though both the peripheral myelin and central myelin provide many of the same physiologic characteristics to the underlying nerve. Furthermore, peripheral nervous system demyelinating diseases usually spare the central nervous system as exemplified in GBS, diabetes mellitus, and hereditary sensory-motor neuropathies.
Accordingly, it would be advantageous and desirable to have a method for treating peripheral nervous system demyelinating diseases. The use of aminopyridines, specifically, 4-aminopyridine, shows promise in providing a drug for use in the treatment of peripheral nervous system demyelinating diseases, such as GBS, which has previously not been identified in the prior art. The use of 4-aminopyridine for treatment of peripheral nervous system demyelinating diseases fills a long-felt and previously unmet need by medical practitioners and those suffering from peripheral nervous system demyelinating diseases for a treatment modality which can alleviate symptoms of their diseases.
According to the subject invention, there is disclosed a method for treating a patient/subject having a peripheral nervous system demyelinating disease which includes the step of administering to a patient/subject having a peripheral nervous system demyelinating disease a therapeutically effective amount of an aminopyridine compound.